The present invention relates to pre-crash sensing systems for automotive vehicles, and more particularly, to a method and apparatus for improving a vehicle safety system using a transponder and GPS.
Auto manufacturers are investigating radar, lidar, and vision-based pre-crash sensing systems to improve occupant safety. Current vehicles typically employ accelerometers that measure forces acting on the vehicle body. In response to accelerometers, airbags or other safety devices are employed. Also, Global Positioning Systems (GPS) systems are used in vehicles as part of navigation systems.
In certain crash situations, it would be desirable to provide information to the vehicle operator before forces actually act upon the vehicle. As mentioned above, known systems employ combinations of radar, lidar and vision systems to detect the presence of an object in front of the vehicle a predetermined time before an actual crash occurs.
Many vehicles are also equipped with GPS for navigation guidance. Typical GPS receivers can communicate with up to twelve satellites. The determination of which satellite or GPS source communicates with a GPS unit is not coordinated between the GPS units in nearby vehicles and depends primarily on the instantaneous signal strength of the satellites in the region of each vehicle equipped with GPS. Reflection, obstruction and atmospheric conditions affect the signal strength at the location of each GPS receiver. Thus, two GPS-equipped vehicles, which may only be a few feet apart, can acquire different satellites from which to determine their respective location data. This can result in differences between the spatial resolution between the two GPS units in the same spatial zone. The resulting error or drift between the two units can be as much as 10 meters. Because of the potential for lack of resolution accuracy between adjacent GPS units, GPS information sharing between vehicles is not practical or useful for safety applications.
It would be desirable to provide a safety system that takes into consideration the GPS information available from other vehicles to provide vehicle environment awareness and threat assessment for crash avoidance and mitigation.
The present invention provides an improved vehicle safety system that uses transponders and GPS to share location information among nearby vehicles.
The present invention provides a method for operating a pre-crash sensing system for a first vehicle having a global positioning system (GPS). The method includes receiving an acquired GPS satellite identifier and generating first vehicle location data with the GPS system. The first vehicle location is transmitted along with the satellite identifier to a second vehicle across a wireless vehicle network. Location information is also received for a detected second vehicle. In response, the first vehicle transmits a request for updated second vehicle location information using a coordinating satellite identifier. The coordinating satellite identifier is then used by the second vehicle to update the second vehicle location data. In this way, both communicating vehicles are generating and sharing location information from a commonly acquired GPS source.
One advantage of the invention is that the GPS data can be used to enhance the safety systems of vehicles in addition to providing navigational guidance.
Other aspects and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims.